LUBBOCK, Texas - You've heard of artificial limbs and even an artificial heart.

Now, researchers at Texas Tech Health Sciences Center say they have created an artificial blood substitute that can be used safely in humans.

The U.S. Food and Drug Administration began clinical trials on the new blood substitute in April.

If approved, the product would save millions of lives a year, researchers predict.

"It literally could have an impact on the health of the world, just as the polio vaccine did and just as antibiotics did," Dr. Bernhard Mittemeyer, interim president of the Health Sciences Center, said recently.

Every 3.75 seconds, a person in the United States requires a blood transfusion.

At the same time, the rate of blood donation is falling. In the U.S., a blood shortage of 3 to 4 million units a year is predicted by 2030, HSC researchers say.

The need for blood is even higher in developing countries.

If fully developed, the market for blood substitutes would be enormous. Some analysts have projected that it could become a $15 billion a year industry in the United States alone.

The idea of using animal blood in humans has been around for decades. The problem until recently has been finding a way to make animal blood non-toxic to humans.

Researchers at the Health Sciences Center say they've developed a method to counteract the toxic properties in the bovine hemoglobin.

The method has been patented by the Health Sciences Center and is licensed to HemoBioTech Inc., a Dallas-based company that is helping fund the Health Sciences Center's research of blood substitutes in hopes of offering the product commercially once it's developed.

Dr. Jan Simoni, who along with researchers Mario Feola and Peter Canizaro discovered the method of dextoxifying the blood substitute, says the process is a medical breakthrough.

"We've got it," Simoni said during a recent tour of his research center at the Health Sciences Center.

"It's not science fiction anymore. It's reality."

Simoni, associate clinical professor at the Health Sciences Center, has been touring the world to lecture at hospitals and universities on the topic of blood substitutes.

The product has already been tested on people in Italy and Africa and showed favorable results, Simoni said.

Besides the obvious benefit of supplying additional blood, a product like HemoTech would have other advantages over conventional blood. One such example is storage.

Human red blood cells must be refrigerated and are only good for 42 days. HemoTech can be stored for up to a year and doesn't need to be matched to a donor's particular blood type.

Contamination of donor blood with infectious viruses such as HIV also could be eliminated through the use of blood substitutes, researchers say.

The research program at the Health Sciences Center uses six cows kept at a facility in New Deal to provide blood for the experiments.

If approved someday for human use, 600,000 cows could provide enough bovine blood substitute to provide the entire world with a blood supply.

Several other companies in the United States also are trying to find a blood substitute.

The first hurdle is obtaining FDA approval, a process that Mittemeyer says could take a couple of years.